The invention relates to micro devices, and in particular, for micro devices having a solution process that needs a uniform thickness therein due to capillary force.
Inkjet dispensing technique may be used to manufacture said micro devices, such as color filters, organic electroluminescent displays (OELD), micro lens, printed circuit board, and detection chips. During manufacture, a pattern with trench structure is pre-defined on a substrate to form a pixel element. The trenches are purposed to induce a uniform film generated on the substrate by ink-jet dispensing. Since ink-jet dispensing is unstable in the early stage and may deteriorate the substrate. Typically, the dispensing behavior becomes more stable after early stage, about several hundred drops ejected. Experience shows that the early-instable and following-stable behavior will cause the pressure difference which is generated due to capillary force along with the printing direction. It makes the thickness of the film may be non-uniform along the printing direction. Furthermore, if the trench is closed structure, the defect near ends of the pixel becomes serious since the pressure difference was balance by the close end, and form white omission at both ends of trench.
US Pat. No. 2003/0193057 discloses an organic light emitting diode and method for producing the same. Referring to FIGS. 1a-1c, to manufacture the organic light emitting diode, an electrode layer 2 is first formed on a substrate 1. A first insulation layer 3 and a second insulation layer 4 are then formed on the electrode layer 2. Finally, barriers 8 are formed at both ends 41 and 42 of a channel 40 formed by the second insulation layer 4. The thickness difference of organic polymer layers 5 and 6 filled in the channel 40 may be reduced by the barriers 8. Nevertheless, the insulation layers are formed by two steps, and the barriers are formed in the channel, thus complicating the process.